Fused cutout



Feb. y2v, 1943.

p. c. HUBBARD FUSED cUToUT Filed April 14, 1941 4 Sheets-Sheet l Feb. 2, 1943. D. c. HUABBARD FUSED CUTOUT Filed April 14, 1941 4 Sheets-Sheet' 2 Feb. 2, 1943.V D. Ac:. HUBBARD 2,309,698

' FUSED CUTOUT Filed April 14, 1941 4 sheets-snaai 3 Feb. 2, v1943. D. c. HUBBARD FUSED CUTOUT Filed April 14, 1941 4 SheefsSheet 4 Patented Feb. 2, 1943 UNITED STATES PATENT GFFlCE FUSED CUTOUT David C. Hubbard, Centralia, Mo., assignor to A. B. Chance Company, Centralia, Mo., a corporation of Missouri 18 Claims.

The present invention relates to fused cut-outs and is particularly concerned with fused cut-outs of the type adapted to be enclosed and utilized on high tension transmission circuits. For example, the device illustrated is proportioned and designed for 50 amperes at 5,000 volts, and it is to be understood that devices embodying my invention may be constructed for use at various voltages and for breaking various currents by variations in the size, spacing, etc. of its component parts, which will be evident to one skilled in the art, from the following description of the invention.

One of the objects of the invention is the provision of an enclosed fused disconnect of such a construction that the housing remains closed during and after operation, so that it is adapted to protect the interior mechanism from the action of the elements, such as rain, sleet, snow, ice, etc.

Another object of the invention is the provision of a fused disconnect in which the dangling fuse leader, which appears after the circuit has been broken by the fuse, is not energized, thus eliminating the hazard which is presented by an energized leader, such as is present in the devices of the prior art.

Another object of the invention is the pro vision of an improved fused disconnect in which the fuse mechanism provides a double break in the circuit, thereby aiding in snuing the arc, one

break occurring within the fuse tube, at the ruptured fuse element, and another break occurring at the point of contact of the fuse unit with a contact carried by the housing.

Another object of the invention is the provision of an improved fused disconnect in which the clip for supporting the fuse unit carries no current, so that the resiliency of the spring clip is not affected by the passage of current, and the device may be used for a long period of time without bad effects on the resiliency of the spring clip.

Another object of the invention is the provision of an improved fused disconnect in which the electrical connecting contacts of the brush type are provided, and in which these contacts are provided with current carrying pigtails or lea-ds so that the contacts will not be affected by the passage of current and so that they will retain their resiliency for a long period of time. This also eliminates the possibility of the sticking of the fuse assembly because of burned or corroded clip contacts.

Another object is the provision of an improved fuse disconnect assembly in which the fuse assembly may be removed by a disconnect stick, thus eliminating the necessity for the operator to approach line parts with his hand for removing or replacing this unit.

Another object of the invention is the provision of an improved disconnect which effects a triple contact break on manual operation, thereby tending to reduce the intensity and length of arc formed when the circuit is broken.

It is a further object of the invention to provide for the breaking of the circuit rst at the top contacts of the assembly so that the tendency for the formation of an arc at the bottom contact is thus eliminated or reduced. As an arc has the tendency of traveling upward and spreading to other parts, this breaking of the circuit at the top, first, reduces or substantially eliminates the possibility oi damage by the formation of an arc below, which might travel upward.

Another object of the invention is the provision of an improved housing structure by means of which the breakage of the porcelain boxes at the hinge points may be eliminated, or at least the construction may be such that if the box breaks, the cover may be held by the improved reinforcing devices provided according to the invention.

Another object of the invention is the provision of an improved housing construction so that if the door is broken in two, the contacts at the top Will swing out, opening the circuit through a double contact break, but the fuse assembly will not be dislodged.

Another object is the provision of an impro-ved structure for securing contacts, clips, latches, etc. of a metallic nature to a porcelain or glass housing member with a minimum amount of labor in the construction of securing devices.

Other objects and advantages of the invention will be apparent from the following description and the accompanying dra wings, in which similar characters of reference indicate similar parts throughout the several views.

Referring to the four sheets of drawings accompanying the specification,

Fig. l is a side elevational view of an enclosed fuse disconnect switch constructed according to the invention, shown in connection with one preferred mode of support;

Fig. 2 is a transverse sectional view, taken on the plane of the line 2-2 of Fig. l, looking in the direction of the arrows;

Fig. 3 is a front elevational View or" the disconnect assembly with the cover removed;

Fig. 4 is a sectional View taken through the device of Fig. l, on the plane of the line 4 4 of Fig. l, looking in the direction of the arrows;

Fig. 5 is a vertical sectional view, taken on the plane of the line 5 5 of Fig. 3, with the cover on the box and the parts in the closed circuit position;

Fig. 6 is a view similar to Fig. 5, with the parts in the open circuit position, the fuse having been ruptured;

Fig. 7 is a fragmentary sectional view through the fuse assembly;

Fig. 8 is a sectional view, taken on the plane of the line 8-8 of Fig 6;

Fig. 9 is a sectional view, taken on the plane of the line 9-9 of Fig. 6;

Fig. l is a fragmentary sectional view similar to the lower end of Fig. 5, with the target in the position which it assumes when itis forced downward by the spring I33 on rupture of the fuse;

Fig. ll is a bottom end view of the fuse assembly;

Fig. 12 is an inside view of the cover, taken on the plane of the line I2-I 2 of Fig. 5;

Fig. 13 is a fragmentary sectional view, showing the preferred mode of securing the supporting bolts for the housing in the body of the housing;

Fig. 14 is a fragmentary sectional view of the structure of an improved mode of support of the spring clips and contacts on the housing or cover of ceramic materials;

Fig. l is a plan view of the securing device of Fig. 4, with the spring clip removed, showing the details of its structure.

Referring to Fig. 1, the fused disconnect is there indicated in its entirety by the numeral I0, and it preferably comprises an insulating housing, such as a housing of porcelain or the like, which is provided with a pair of rearwardly extending threaded metal studs II, I2 located on and proiecting from the rear side I3 of the housing.

The studs I I may be used with strap metal bracket members I4, I 5 for securing the assembly to a cross arm I6. Each of these bracket members I4, I5 comprises a metal strap having a pair of flanges I1 at right angles to each other, the length of these flanges being equal to the height and width of the cross arm.

Each of these brackets I4, I5 also has a pair of diagonally extending attaching flanges I8, I9 at two diagonally opposite corners of the cross arm I6, and the attaching flanges are provided with apertures for receiving the screw bolts 20, having nuts 2 I, whereby the brackets are clamped on the cross arm I6.

The bracket I4 preferably has its attaching flange I8 provided with an extension and with the supporting flange 22 extending upward at an acute angle, and provided with apertures for receiving the studs II, I2. The nuts 23 clamp the flange 22 of bracket I4 against the housing I3, the studs having their heads embedded in the porcelain, and lock nuts 24 may be employed to assure the xity of the nuts 23.

I desire it to be understood that any of the various types of supporting brackets may be used, although the one illustrated is one of the preferred forms, as it supports the housing in such position that the cover will remain open, when opened to a predetermined point.

The housing of the fused disconnect I0 preferably consists of two parts, the main housing member 25 (Fig. 1) and the cover 26. The main housing member preferably is of substantially box shape, having a relatively thick rear wall 21 and a pair of thinner forwardly extending walls 28, 29 at each side.

The front of the main housing member 25 is open so that it may be closed by the cover 26, which is adapted to be received between parts of the side walls 28, 29. The side walls 28, 29 and rear wall 21 define a fuse unit chamber 30, the upper end of which is closed by the upper wall 3| (Fig. 5) and the lower end of which is partially closed by a lower wall 32, all of these walls being integral with the main housing member 25.

The lower wall 32 is cut away at 33 to permit the passage of a target 34 carried by the fuse assembly, which is indicated in its entirety by the numeral 35. This lower wall is also cut away to provide an opening at 36 (Fig. 3 and Fig. 6) immediately below the lower end of the tube of the fuse assembly 35, which encloses the fuse.

Thus the lower end of the housing is open at all times for projection of the target 34, which indicates that the fuse is ruptured, and to permit the fuse, which is blown out of the tube 31 to dangle downward out of the housing, where it is blown by the force of gases produced 'by the rupture of the circuit and fusing of the fuse in the tube 31.

The side walls 28, 29 are preferably rabbeted as at 40, thus providing a shoulder 4I (Fig. 4) for engagement with the cover 26, and laterally projecting flanges 42 project beyond each side of the cover 26. This provides a more effective closure for the fuse assembly against the action of the elements.

At the upper end of the housing the side walls 28, 29 are provided with ears or extensions 43, serving as a support or hinge for the cover 26, by means of a pintle 44. These hinge ears 43 have been subject to breakage, and the side walls of the housing are preferably provided with grooves 45 of rectangular cross section for receiving a reinforcing galvanized iron strap 46 of substantially U shape, which ts in the grooves through a cylindrical bore 43, which is located in and traverses the cover 2E.

The upper wall 3! preferably does not extend outward as far as the ears 43, terminating at curved edge 48 (Fig. 5), which serves as a stop member for supporting the cover in open position, as indicated in dotted lines in Fig. 6.

The housing is also rabbeted inside the two ears 43, the shoulder 4I (Fig. 3) extending the full length of the side walls 28, 29 and across the rear wall at 50, inside the fuse assembly chamber 30.

The rear wall 21 of the main housing member IU is preferably not of uniform thickness, but is provided with portions of different thickness. dividing the chamber up into a number of different parts, and providing support for a number of different switch elements, as follows:

At the upper end of the chamber the rear wall is provided with a flat shelf at 5I, providing a support for the fuse assembly hinge, indicated in its entirety by the numeral 52. The fuse assembly hinge consists of a metal member, havlng a flat attaching flange 53, and a pair of downwardly and outwardly extending bearing flanges 54, located at right angles to the attachment flange 53.

The attachment flange 53 is secured in place by a pair of screw bolts 55, passing through apertures in the attachment flange 53, and threaded into nuts or equivalent threaded members 56, embedded in the porcelain body of the rear wall 21. The bearing flanges 54 extend outward and downward, and are each provided with the inwardly extending and downwardly curved slots 51, the trunnions 58 carried by the fuse assembly 35.

The lower part of the bearing flanges 54 take the form of a hook 59 so that the trunnions 58 may be inserted by an upward and lateral movement and brought to rest on the hooks 59 by dropping the fuse assembly into place.

The flanges 54 are spaced from each other by a distance equal to the lateral thickness of the fuse assembly at its upper end. The member 52 acts as a pivotal support for the fuse assembly, but is insulated. Its parts carry no current, and thus there is no possibility of the fusing of the pivotally mounted parts 58 and 54.

The fuse assembly chamber 39 is preferably deepest at the surface G (Fig. 5), which fiat surface serves as a support for a contact and connector arm, indicated in its entirety by the numeral 6I. This contact and connector arm 6I comprises a member made of conducting metal, such as copper, having a body portion 920i sub stantially rectangular cross section, and preferably provided with a through bore 63 extending axially through the body portion 62.

A pair of threaded bores 64 extends` from the outer surface 65 of the body portion 62 into cornmunication with the bore 63, and these threaded bores serve to receive the screw bolts 66, which are adapted to extend into the bore 83 and clamp a conductor in this bore.

The body portion 62 of connector is preferably formed with an anchoring formation 61, which may extend into the porcelain rear wall 21, and may be anchored therein to hold the connector in its proper position.

The anchor 61 may be of dove-tailed or other desirable shape, and is preferably of substantial length, to assure the anchoring of the connector in the housing. The side walls 28, 29 are preferably formed with the cylindrical through bores R8 registering with the bore 63 in the connector 6| at each end, and the bores 88 in the housing walls are of larger size, adapted to receive not only the conductor, but its insulating covering, the end of the insulating cover being brought into abutting relation with the flat end of the connector body 62.

As bores are provided in the side walls at each side, and the bore in the connector is a through bore, the connections may -be made from either side of the housing, the screw bolts 66 being brought into clamping relation with the conductor in the bore B3.

The housing walls 28, 29 are provided on their outer faces surrounding the through bores 68 and similar bores 69 within outwardly projecting rib of substantially U shape in elevation, as shown in Fig. l, the ribs being preferably curved and substantially half cylindrical in cross section.

These curved ribs have their legs extending downwardly, and serve to facilitate drainage. of water from the face of the housing and to prevent in some measure the access of water to the interior of the housing, by reason of such drainage.

The connector body 62 isprovided at one end (the yleft in Fig. 3) with an outwardly projecting contact arm 1I, which may extend at right angles to the main body 62, and may be substantially rectangular in cross secton. At its outer end itr is preferably provided with a head 12, which may be rectangular in shape, and which may provide a larger plane contact area 13 on its outer face.

The face 13 is located substantially on the same plane as the outer edge of the ribs 42 of the housing (Fig. 4), and the arm 1| is located slightly inwardly of the side wall 28 in the chamber 30, for engagement with a contact, further to be described.

In order to separate the upper contacts of the assembly from the lower contacts, the main housing member 25 is preferably provided with a partition 14 (Fig. 3, Fig. 5) located below the connector 6l, and slightly higher than midway ibetween the ends of the housing.

This partition 14 has its outer edge 15 flush with the rabbeted shoulders 4l and 59 of the main housing member, and the partition 14 is tapered in thickness toward the outer edge for convenience in molding. In the same way the housing walls 28, 29 may taper in thickness toward their outer edges, and the chamber 39 may be narrower toward its bottom for convenience in withdrawal of the mold parts.

The partition 14 is preferably provided with a U-shaped groove 15, the walls of which are slightly spaced from the insulating tube 31 of the fuse assembly 35, so as to permit the fuse assembly to be placed in the chamber 39 in position traversing the partition 14.

The rear housing wall 21 is provided adjacent its lower end, but spaced therefrom, with another shelf 11 adapted to provide a support for a spring clip 18, which engages the tube 31 of the fuse assembly 35 and holds it in closed circuit position.

The spring clip 18 (Fig. 6) has a fiat attaching flange 19, through which a pair of screw bolts B9 pass, and the screw bolts are threaded into nuts or equivalent threaded members 8l, embedded in the porcelain body 82. The attaching flange 19 of the spring clip 18 supports a pair of spring flanges 83 of identical shape, but oppositely disposed. These spring flanges each have a diagonally outwardly extending straight portion 84 and a curved tube-engaging portion 85, which is partially cylindrical. At their outer edges the spring flanges 83 are provided with outwardly curved lips 86, spaced sufficiently so that when these lips come into engagement with a tube of the size of the tube 31 of the fuse assembly the spring flanges 83 are cammed apart.

Further pressure on the tube 31 into the spring flanges S3 causes the tube to come to rest in the position of Fig. 4, where its opposite sides are engaged by the cylindrical portions 85 of the spring flanges 83. It should be noted that this spring clip engages only the insulating tube 31 and holds the fuse assembly in place, but it does not carry any current, and there is no possibile ity of the spring clip parts becoming fused or of the switch parts sticking due to fusing of the clip.

At its lower end the fuse assembly chamber 39 is again provided with a deeper portion at the flat surface 81 on the inside of the rear wail 2l cr the purpose of supporting another connector This connector comprises a lbody portion of substantially similar shape to the body 62 of the connector 6|, and it likewise has the through bore 63 for receiving the conductor, the through bore being in registry with the apertures 69 in the side walls.

This connector is likewise provided with the clamping screw bolts G6, and it is likewise anchored to the porcelain body 25. At its left end this connector body 88 has an outwardly extending integral lug 89, the right face of which serves as a iiat shoulder engaging at the edge of a spring contact 90, which may thus be secured in place against rotation by a single screw bolt 66 passing through the contact 90 and threaded into the connector body 88 (Fig. 6).

This contact member comprises a strip of resilient electrically conducting metal, such as spring bronze of adequate thickness to assure its having a certain degree of stiffness, and it may be curved backwardly at 92 and outwardly again at 93 and backwardly at its tip 94.

Its curved face at 93 serves as the contacting portion of the contact, and its end is connected by solder to one end of a braided copper pigtail or lead S5, the other end of which is provided with an aperture for receiving the screw bolt 66 so that it may be clamped between the connector body E8 and the contact member 90.

rThe braided copper wire pigtail 95 being soldered to the rear side of the contact 9| at its end, and being in good electrical connection with the connector 80, the spring contact 90 does not need to carry anything but a negligible amount of current, most of the current going through the pigtail. Thus its resilient characteristics will not be impaired, even though it is used for a long period of time at its rated current.

The spring contact 90 projects downward into the groove 33, from which the target projects. This Contact is adapted to engage a contact carried by the target and fuse assembly further to 'ce described.

The fuse assembly or fuse unit, indicated in its entirety by the numeral 35, is removable as a unit from the chamber 30, and it is adapted to be handled by means of an ordinary disconnect or fuse stick. For this purpose its upper metal fitting (Fig. 6) may comprise a cast metal member of substantially cylindrical shape at its lower end, except that it is provided with a plane surface |0| on its face.

It also has above this face an integral forwardly projecting arm |02 with a pair of downwardly extending prongs |03, |04 (Fig. 3). These prongs |03, |04 are spaced from each other by the upwardly extending groove |05, which is bounded by the two parallel edges of the prongs |03, |04 and by a circular upper portion at |06.

The spacing between the prongs |03, |04 and the plane face |0| is suicient to receive the relatively flat circular head of the fitting at the end of a fuse puller, and the width of the groove 535 is sufficient to receive the shank of this fitting on the end of a fuse puller so that the fuse assembly 35 may be lifted and handled very conveniently by means of an ordinary fuse puller.

The lower surface |01 of the forwardly projecting arm |02 is also substantially plane, although this may be of no importance where a round headed fuse puller is employed.

The metal fitting |00 is provided with an axially extending bore 00 extending into its lower end and adapted to have a tight frictional engagement with the cylindrical outer surface of the insulating fiber tube 31.

It also has an inwardly extending annular flange |09 at the end of the bore |08, the flange |09 defining a smaller bore ||0 through which the fuse passes.

At its upper end the fitting |00 has a threaded counterbore and the iiange |09 has an upper plane surface ||2. The threaded counterbore is adapted to receive a closure plug ||3, having a threaded portion 4 and a head provided with an overhanging annular ledge ||5 that overhangs the plane annular end surface ||6 of the fitting |00.

The closure plug ||3 has a flat lower end ||1 adapted to engage the flat top of the button ||8 of the fuse, which has a cylindrical portion ||9 in the aperture ||0.

Any type of commercial fuse having such a button and a fusible portion, and a flexible pigtail, may be used in this fuse assembly, the one illustrated being constructed as follows.

The fuse head is preferably of relatively harder material and is provided with a fiat ribbon-like shank |20 extending downward from the cylindrical portion ||9. This shank has a circular groove at |2| providing a portion of reduced cross section at this point.

The ribbon shank |20 is secured by s Adering or brazing to a fuse wire |23 at |22, the lower end of which is secured in a copper tube |24 by soldering, the copper tube being secured by a sheet metal clip |25 and by soldering to the flexible stranded conductor or pigtail |26.

An annular collar |25' on the copper tube |24 engages one end oi an insulating fiber tube |26', which is confined between the collar |25 and the end of the ribbon shank |20, housing the meltable portion of the fuse.

When located in the fuse assembly, this fuse has its button ||8 resting on the annular shoulder ||2 and clamped against it by the closure plug ||3. The main part of the fuse extends downward into the fiber tubing 31, and the pigtail projects from the lower bent end of the fiber tube 31, where it is secured in a manner further to be described.

The upper end cf the fitting |00 of the fuse assembly (Fig. 6) is provided with a pair of oppositely located trunnions 58 (Fig. 6) of cylindrical shape and adapted to be received in the slot 51 on the hook 59 of the upper supporting fixture 52 of the housing |0.

These trunnions 58 support the fuse assembly for pivotal movement on the common axis of the two trunnions, but they permit the removal of the fuse assembly by a lifting and outward pulling movement which is applied by means of a fuse puller having its head behind the prongs |03, |04 (Fig. 3). Two usual positions for the fuse assembly are shown in Fig. 5, where the fuse assembly is secured with the cover closed, and in Fig. 6, where the fuse assembly hangs loosely after the cover has been opened, the fuse having been ruptured.

The insulating tube 31 comprises a tube of indurated fiber or other suitable insulating material, the fiber being impregnated with an insulating compound, such as a phenolic condensation compound, dissolved in suitable solvents. It is of suflicient length to house the fuse and part of the fuse pigtail |26 so that the fuse pigtail extends from the lower end of the tube, as shown in Fig. 3.

Adjacent its lower open end, but slightly spaced therefrom, the insulating tube 31 supports another metal xture, indicated by the numeral |21.

This metal fixture comprises a cast metal member, oval in plan, and formed with a pair of parallel axially extending bores |28, |29. The bore |28 has a tight frictional t on the insulating tube 31, and the bore |29 terminates in an annular shoulder at |30, and has a similar t on another similar insulating tube |3|. The insulating tube |3| is adapted to house the plunger |32, which is spring pressed downward by the compression spring |33 (Fig. 6) to place a tension on the fuse.

The insulating tube |3| is also of indurated and impregnated ber, but, as it is not used to house the fuse, it may be provided with a thinner wall, as shown in Fig. 6. It is of suitable length to house a fairly long compression spring |33, and the plunger |32, and, as shown, it extends upward slightly more than` half way the length of the fuse tube 31. At its upper end the insulating tube |3| is closed with an insulating plug |34, secured in place by a transverse metal pin |35, passing through the plug tube, and riveted over at each end.

The plunger |32 (Fig. 6) comprises a cast metal member, having its main portion |36 of cylindrical shape, but provided with a laterally projecting flange |31 of substantially rectangular cross section.

At its lower end the plunger |32 pro-vided with an enlargement serving as a target 34 and also as a contact. This enlargement comprises a larger cylindrical body portion |33 integral with the cylindrical shank |36. lThe body pore tion |38 supports a laterally projecting arm |39 of rectangular cross section, terminating in a contact head |46, which is wider, in order to provide the flat contact face |4| of greater area.

The target 34 also has a laterally and downwardly extending integral arm |42 (Fig. 3), the end of which is provided with a head |43, having a partially circular groove |44 for engaging the fuse pigtail |26. The target 34 also has a threaded bore |45 for receiving the screw bolt |46, and the bolt |46 carries a special washer |41, having a tangentially projecting arm |48, which is turned upward at |43 to engage the arm |39, preventing rotation of the washer.

All of the parts of the target 34, including the .screw |46 and the washer |41, are of metal of high electrical conductivity, as it forms a part of the electrical circuit.

At its upper end the plunger |32 is provided with a substantially cylindrical head |50, which may be secured on the plunger by means of a threaded bore engaging a reduced threaded portion |52 and an annular shoulder |53 on the plunger |32.

A screw driver slot |54 is provided in the upper end of the head, in order that it may be driven home on the threaded portion |52. The spring |33 is compressed between the closure plug |34 and the head |50 of the plunger |32, urging the plunger |32 and the target 34 downward.

The side of target 34 may be painted red or some other distinguishing color, so that it may be more conveniently observed when it projects from the housing.

The tting |21 is also provided on its front side, near its lower edge, with an integral downwardly projecting hook or shoulder member |55, having the ilat shoulder |56 on its inner side,

This at shoulder |56 is adapted to engage the inside surface of a keeper |51, carried by the cover 26 (Fig. 5), when the cover and fuse assembly are in the closed position of Fig. 5.

The arrangement of the pivotal supports of the fuse assembly 35 and the cover 26 on the housing I|0 are such that the shoulder |56 and keeper |51 slide out of engagement with each other as they come to the position of Fig. 6 from that of Fig. 5. Therefore, the length of the shoulder |56 bears a denite relation to the lengths of the cover and fuse assembly and to the points of pivot of these latter.

The fuse assembly is adapted to be held in its closed position, that is, the position of Figs. 3, 4 or 5, by the engagement of the spring clip 18 with the sides of the tube 31, as shown in Fig. 4. This spring clip carries no current and engages the insulating tube and holds it in the housing,

from which it may, however, be pulled by means of the cover 26, keeper |51 engaging behind the hook |55.

As the spring clip 18 carries no current, its resiliency will not be affected by any kind of use to which it is subjected, and it will operate for a long period of time without necessity for repair or replacement.

When the fuse assembly is in this position, the Contact head |40 of the target 34 engages the contact 90, as shown in Fig. 5; but when the fuse is ruptured, the target moves downward to the position of Fig. 10.

Referring to Fig. 3, the mode of installation ol a fuse will be apparent to one skilled in the art, from the arrangement of the parts illustrated therein. The pigtail |26 of the fuse passes out of the lower end of the tube 31. The plunger |32, having been forced upward to the position of Fig. 3 by hand, the pigtail |26 is located in the groove |44 of the target arm |42 and brought over on the arm |42, where it is further guided by a downwardly extending flange |58 (see Fig. 1l). From there the fuse pigtail |26 passes under the Washer |41 and is comined between the shank of the bolt |46 and the upwardly projecting arm |49 of the washer.

The pigtail may be given more than a full turn about the screw bolt |46 until its loose end emerges from beneath the washer |41 on the other side of the upwardly projecting lug |48. The screw |46 then being driven home, it will clamp the washer against the pigtail and assure the rm securement of the pigtail of the fuse to the target, with a good electrical contact.

The cover 26 may also comprise an integral porcelain member of substantially rectangular shape in plan and fitting in between the ribs 20 on the main housing against the rabbeted shoulders 4| and 50. For this purpose the cover may be formed with a pair of inwardly projecting ribs |60y (Fig. 4) which engage the shoulders 4|, the inside of the cover being relieved at |6| between the ribs to make it slightly hollow and provide more space in the fuse assembly chamber 30.

The cover is preferably made thicker at its upper end portion. The middle section of the cover is shown in Fig. 4, and here it is preferably provided with a vertically extending outer reinforcing rib |62, which extends downward and is widened at its lower end (Fig. 5) to provide sulcient stock for the transverse aperture |03 (Fig. 5). This aperture is of sufficient size to receive the head of a fuse stick so that the head of the fuse stick or the hook of some other hot line stick may be inserted in the aperture |63 to pull the cover open.

At its lower end, adjacent the lower fuse assembly fixture |21, the cover is formed with a larger recess |64, providing space for this iixture and for the latch |55 and keeper 51. The recess |64 is closed by a lower end wall |65 (Fig. 6), which, however, is provided with an inwardly extending groove |66 (Fig. 6) between the side ribs |60.

The base of this groove, that is, the flat surface |61, engages the flat ange |68 of the keeper |51. This keeper may consist of a strap of sheet metal, having a U-shaped portion |69 that is provided for the purpose of increasing the resiliency of the keeper.

rIhe lower side of this U-shaped portion engages the flat inner surface of the wall |65, and this leg carries the flange |68, which engages the surface |61.

With this arrangement a, single screw bolt |10, passing through the yoke of the U-shaped portion of the keeper |51, may be threaded into a threaded member 1| embedded in the porcelain to secure the keeper to the cover, without any possibility of rotation.

The other leg |69 of the U-shaped portion of the keeper |51 has the upwardly extending harige |12, which engages the shoulder |56 on the fuse assembly (Fig. 5).

At its upper end the cover 26 is preferably made thicker so that it may have a recessed portion |13 (Fig. 5) of sufficient depth to house the forwardly projecting prongs |03, |04 on the fuse assembly, and also for the purpose of providing space for a pair of contact members |14, |15 (Fig. 12).

These contact members are identical in shape, and are both carried by a conducting metal bridge |16, consisting of a rectangular bar of metal, having a pair of apertures 11. The apertures |11 are counterbored so that the heads of the screws |18 are depressed, and screws |18 pass through the aperture |11 and are threaded into threaded nuts |19 or other equivalent, embedded in the porcelain of the cover.

Thus the bridge |16 is fixedly secured to the cover and it extends from inside of one rib |60 to the inside of the other rib.

In the commercial embodiment of the invention I propose to make a bridge |16 and contacts |14, |15 all of one piece, in which case the pigtails 8| would be secured to the contacts by means of a screw and washer, instead of being clamped between the bridge and contact.

At each end the bridge |16 is rabbeted at |80 to provide space for attachment of a pigtail IBI, and one of the contacts |15 or |14.

A screw bolt |82 passes through each contact |15 cr 14, and through the braided pigtail |8|, and is threaded into the bridge bar |16, clamping that end of the pigtail against the bridge bar. The other end of the pigtail |8| is soldered or brazed to the rear side of the contact.

The edge of each contact |14 or |15 engages the rabbeted shoulder at |60 so that only one screw |82 is necessary to secure the contact and pigtail to the bridge bar against rotation.

The major portion of the current is carried by the pigtail |8i, thereby preventing the generation of heat in the contact, which would destroy its resiliency. The shape of the two contacts |14, |15 may be substantially the same as the contact 9|, previously described.

The contact |14 is located to engage the nxed contact head 13 carried by the housing. The contact |15 is located to engage a part of the flat surface |0|, further indicated at |84 (Fig. 3) as a contacting portion of the upper fuse assembly fitting |00 The location of the contacts |14, |15 on the cover is such that when the cover is closed and the fuse assembly is supported by the spring clip 18, as shown in Fig. 5, the contacts |14, |15 engage the contacts 13 and |84.

At its upper end the cover 26 is preferably provided with a heavy forwardly projecting lug or hinge arm |90, which preferably extends the full width of the cover and serves to support a` pintle for the hinge.

This lug is provided with a transverse bore |9| for receiving the pintle 44, whereby the cover is pivotally supported at a point forward of the pivotal support of the fuse assembly.

The fused disconnect is preferably mounted at an angle, substantially the angle shown, which brings the pintle 44 of the cover and the trunnions 58 of the fuse assembly into about the same level, and enables me to bring about the cooperation between the lower ends of the fuse assembly and the cover involving the engagement of the keeper |51 with the shoulder |56 when the parts are in the position of Fig. 5, and their disengagement in the position of Fig. 6.

By providing the cover with a heavy pintle arm across its full width there is less danger of breakage of the cover across this arm, and greater resistance against abuse may be expected.

The circuit may then be traced as follows: One of the line conductors may come in at one of the apertures 68 of the housing, being engaged with the connector 6I (Fig. 5) in the bore 63, by screws 66. Current passes through the arm 1| to contact head 13, contact |14, pigtail IBI, bridge |16, other pigtail |8|, contact |15, contact surface |84 of the fuse lit-ting |00, fuse button ||8, fuse |23, fuse pigtail |26, target head 34, contact |4I, contact surface 93, pigtail 95, connector 88, to conductor in the bore 63, emerging from aperture 69 of the housing.

The operation of the fused disconnect is as follows: The arrangement of the fuse in the fuse unit has already been described, and when this is done, the parts of the fuse assembly will be in the position of Fig. 3. Assuming the fuse assembly is in the housing and the cover closed, and the fused disconnect switch is connected in the circuit, the device is now in the position of Fig. 5 and adapted to protect the circuit. Upon the passage of a current sufficient to rupture the fuse, the fuse will be ruptured and the explosive action of the gases will cause the ruptured fuse to be driven out of the lower end of the insulating tube 31.

The dangling end of the fuse, carried by the pigtail |26, is withdrawn from the end of the insulating tube 31 by plunger |32, actuated by the spring |33. Rupture of the fuse will thus permit the target 34 to move from the position of Fig, 5 to that of Fig. l0, where it will project from the lower end of the housing, and will indicate that the fuse is ruptured.

Thus it is not necessary to open the housing to ascertain whether the fuse is ruptured, but the lineman can see at once the condition of the fuse, Without opening the housing.

Assuming that the fuse has been ruptured, it may be replaced as follows: A disconnect stick may have its head inserted in the aperture |63 of the cover. A pull exerted on the cover will be transmitted by the keeper |51 to the shoulder |56 of the fuse assembly. The fuse assembly and the cover will, therefore, pivot as one unit at the beginning of their motion away from the housingl and the cover will pull the fuse tube 31 out from between the legs of the spring clip 18,

After this amount of movement of the cover and fuse assembly together, the arrangement of the pivots of the fuse assembly at 58 and the cover it is such that the keeper flange |12 moves out of engagement with the shoulder |50 of the fuse assembly, and the fuse assembly hangs free ci the cover, as shown in Fig. 6. The cover may then be opened farther by means of the disconnect stick and may pivot upward to the dotted line position of Fig. 6, where it will rest backward against the stop surface 49, with the housing entirely open.

The disconnect stick may then have its head inserted in the slot |06 between the legs |03, |04 of the fuse assembly, and the fuse assembly may be lifted from its upper supports 59 by the disconnect stick. The fuse may be replaced and the fuse assembly then again replaced as a unit by means of a disconnect stick. In this replacement of the fuse assembly the trunnions 58 are again placed in the slot 51, the fuse assembly, with its fuse, hanging freely from its trunnions.

The cover may then be pivoted downward until the bridge |16 engages the face of the insulating tube 31 and forces the insulating tube to pivot with the cover. The insulating tube will then be forced in between the legs of the spring clip 83, where it will be retained to hold the cover and fuse assembly' in the position of Fig. 5.

During this motion of the cover and fuse assembly the pivotal arrangement of the cover and fuse assembly is such that the keeper |51 has moved up behind the shoulder |56 on the fuse assembly, and the cover is again in position to pull out the fuse assembly, if the cover is opened.

As a general rule, it is not advisable to break the circuit by means of the mechanical contacts on such a fused disconnect, but such a break is nevertheless found necessary by linemen, and it can be effected very quickly by means of the present fused disconnect switch.

When the parts are in the position of Fig. andthe coveris opened, the circuit is broken at three places. It is broken below, between the contact surfaces 93 and |4|, when the cover pulls the fuse assembly tube 31 out from between the legs of the spring clip 18. The circuit is also broken above at two points simultaneously, by disengagement of the contact |14 with the contact surface 13 and disengagement of contact |15 carried by the cover, with the contact surface |84.

When the switch is opened manually, the circuit is broken in three places, thus diminishing the tendency to arc. While a break at a contact located in a low part of the device might tend to cause the arc to spread to other parts, this is prevented by the additional two breaks that are produced at the top.

When the fuse is blown, there is a double break, the circuit being broken at the fuse in the tube and at the lower contact, when the target moves downward. This makes a much faster break of the circuit than anything in the prior art of whichI am aware.

i So far as I am aware, most of the prior art devices have the fuses attached to the cover, and they are not provided with any means forwithdrawing the ruptured fuse from the tube.

The .lower contact break avoids a high resistance path which might occur through the carbonized inside of a tube. On a light overload a fuse may melt slowly, and the tube may burn slowly, thus carbonizing the inside.

In some embodiments of the invention the housing may be made of special glass, such as Pyrex, which would have the additional advantage that cracks in the glass become visible before any denite failure. A glass housing would have the additional advantage that internal conditions would be immediately visible, and insects, such as wasps, which might penetrate to the interior, would be Visible from the outside. With a transparent housing, if an arc occurs at one spring, which might have failed, it would be immediately visible.

By reason of the mode of support of the cover, if the cover should be broken in two, the two upper contacts |14, |15 would be moved outward and would break the circuit through a double contact break, but it would not dislodge the fuse assembly. This condition would immediately become visible to the lineman by mere inspection from the ground.

Referring to Fig. 13, this is a fragmentary sectional View, showing the details of structure of the support of the bolts and |2 in the housing member 25.

The housing member is provided with a pair of suitably located sockets 200, which taper inwardly for convenience in molding, and which are adapted to receive the heads 20| of the bolts. The head 20|, having been located in the socket with the bolt in the desired position, the rest of the socket is filled in with cement 202 surrounding the head and engaging the walls of the socket and the shank of the bolt. This cement may be any suitable cementitious material adapted to have a good bond with the porcelain or the glass, and of an initially plastic, but finally rigid, form.

Referring to Figs. 14 and l5, these views show the details of structure of the threaded members, equivalent to a nut, by means of which the contacts, the keepers, clips, connectors, etc. may be secured to the porcelain housing.

In this case the porcelain housing again has a socket 200, and the threaded member, which is indicated by the numeral 8|, may be a substantially cylindrical body, having the outwardly extending longitudinal ribs 203 and the annular ribs 204, 205.

The anchoring member 8| has a centrally 1ocated threaded bore 206, and at its outer end has a flat body flange 201, which may substantially cover the socket 200. At one end this body flange 201 has a slot 20B, which provides an opening for the surplus cement to escape; or, if molten metal is used, provides a filling hole into which the metal may be inserted.

The body flange 201 preferably has a pair of I outwardly projecting stop flanges 209, 2|0 which engage the opposite sides of the attachment flange 19 of the spring clip. Thus a single screw bolt may serve to secure the spring clip to the anchoring member 8| without any possibility of turning of the clip on the anchoring member 8|.

In this case the anchoring member 8| is again secured in the socket 200 by means of the cement 202, or the socket is filled about the anchoring member by pouring in molten metal, such as lead or solder, which engages the anchoring member and also engages the walls of the socket to anchor the member 8| in the socket.

This form of anchoring is contemplated in the present Adevice with regard to the connector |33,

connector Si, supporting fixture 52, and keeper il, and it; may also be used for the anchoring of the contacts |14, H5 and bridge H6.

The anchoring devices referred to exemplify what is meant when it is stated that the metal part is secured by being embedded in the porcelain housing, as it is either embedded in soft metal or in cement, in a socket.

It will thus be observed that I have invented an improved fused disconnect, having many advantages over the prior art devices. When the fuse leader is thrown out of the present device, it is insulated, because contact has already been broken ai; the lower contact. When the switch is opened, there are multiple gaps produced, which tends to reduce arcing. When the fuse is ruptured, the door stays closed, as distinguished from the devices of the prior art, and the interior mechanism of this device is not exposed to the elements.

The present device is provided with a much stronger housing, and there is no danger that the device may be destroyed by breaking off the ears, which support the hinge. Such disconnect housings are subject to a great deal of abuse, as small boys sometimes throw rocks at them, and hunters shoot at them as targets.

In the present device the fuse unit may be rcrnoved by a switch stick, and it is not necessary to use the hands, as in the prior art devices. The plunger type of fuse withdrawing device is more compact than any of the devices of the prior art, and I believe that the double break in the fuse tube and at the lower contact, breaks the circuit considerably faster than in the prior art devices.

While I have illustrated a preferred embodiment of my invention, many modications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but desire to avail myself of all changes within the scope of Iche appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:

l. In a fused disconnect switch for high tension circuits, the combination of an insulating housing with a fuse unit mounted therein and connectors carried by said housing for establishing connection between a line and said fuse unit, said fuse unit including a fuse tensioned in an elongated insulating housing, and resilient means for withdrawing one end of said fuse on rupture of the fuse, said elongated housing comprising an insulating tube and a spring clip carried by said housing for engaging said insulating tube and retaining said fuse assembly in predetermined position.

2. A unitary fuse assembly comprising an insulating tube having connector means at one end for engagement with one end of a fuse in the tube and for connection to a circuit, and means for tensioning the fuse, comprising a spring pressed plunger carried by the other end of said tube and adapted to be secured to a leader from said fuse to urge said leader in such a direction that it will be withdrawn from the tube on rupture of the fuse, said spring pressed plunger being carried by another insulating tube, and a metallic fitting for securing said two tubes in substantially parallel relation.

3. In a fused disconnect switch, the combination of a housing with electrical connectors carried thereby for establishing an electrical connection to a fuse unit, a fuse unit adapted to be removably carried by said housing and to be connected to said connectors, and a plurality of pairs of switch contacts arranged in series in said circuit and adapted to be broken when said fuse assembly unit is moved from the closed circuit position to the open circuit position.

4. In a fused disconnect switch, the combination of a housing with electrical connectors carried thereby for establishing an electrical connection to a fuse unit, a fuse unit adapted to be removably carried by said housing and to be connected to said connectors, and a plurality of pairs of switch contacts arranged in series in said circuit and adapted to be broken when said fuse assembly unit is moved from the closed circuit position to the open circuit position, and a movable cover carried by said housing, said cover being adapted to actuate said fuse assembly unit to open or close said contacts.

5. In a fused disconnect switch for high tension lines, an insulating housing comprising a main housing member constructed of ceramic materials and having an internal chamber for receiving a fuse assembly unit, a cover for closing said chamber, said main housing member having hinge ears for engaging a. pintle pivotally supporting said cover, and a metal strap carried by said main housing member 4and having its ends also carrying said pintle whereby displacement of the housing by breakage of the pintle ears is prevented.

6. In a fused disconnect switch for high tension lines, an insulating housing comprising a main housing member constructed of ceramic materials and having an internal chamber for receiving a fuse assembly unit, a cover for closing said chamber, said main housing member having hinge ears for engaging a. pintle pivotally supporting said cover, and a metal strap carried by said main housing member and having its ends also carrying said pintle whereby displacement of the housing by breakage of the pintle ears is prevented, said metal strap having predetermined of its parts secured to said main housing by location between opposing shoulders carried by said main housing.

'7. In a fused disconnect switch, the combina tion of an insulating housing with a. fuse assembly unit having a trunnion for pivotally supporting said unit, a bearing carried by said housing for engaging said trunnion, said fuse assembly unit comprising an insulating tube and a spring clip carried by said housing and engaging the sides of said insulating tube for holding said fused assembly unit in predetermined position in said housing.

8. In a fused disconnect switch, the combination of an insulating housing with a. fuse assem-bly unit having a trunnion for pivotally supporting said unit, a bearing carried by said housing for engaging said trunnion, said fuse assembly unit comprising an insulating tube and a spring clip carried by said housing and engaging the sides of said insulating tube for holding said fused assembly unit in predetermined position in said housing, a cover pivotally mounted on said housing, and cooperating means between said cover and unit whereby the cover is held in closed position by said unit and spring clip.

9. In a fused disconnect switch, the combination of an insulating housing with a. fuse assembly unit and means for securing said fuse assembly unit in said housing, switch contact means carried by a. cover movably mounted in said housing and adapted to close the circuit through said unit when said cover is closed, the breakage of said cover effecting an opening of the circuit.

10. In a fused cut-out, the combination of an insulating housing having a recess for receiving a replaceable fuse unit, with a replaceable fuse unit comprising an insulating tube having electrical connectors at its ends,y and having a tensioned fuse extending between said connectors inside said tube, a cover pivotally mounted on said housing and adapted to effect a substantial closure of said recess, means for pivotally mounting one end of said fuse unit on said housing, and a resilient spring clip carried by said housing and adapted to engage said insulating tube to hold said fuse unit in operating position, said fuse unit in its operating position having one of its connectors engaging a contact carried by said housing and held in engagement by said spring clip engaging said insulating tube.

11. In a fused cut-out, the combination of an insulating housing having a recess for receiving a replaceable fuse unit, with a replaceable fuse unit comprising an insulating tube having electrical connectors at its ends, and having a tensioned fuse extending between said connectors inside said tube, a cover pivotally mounted on said housing and adapted to effect a substantial closure of said recess, means for pivotally mounting one end of said fuse unit -on said housing, and a resilient spring clip care ried by said housing and adapted to engage said insulating tube to hold said fuse unit in operating position, said fuse unit in its operating position having one of its connectors engaging a contact carried by said housing and held in engagement by said spring clip engaging said insulating tube, said contact being carried by a connector on said housing, and an electrically conducting flexible conductor extending from said connector to said contact at a. point adjacent the contacting portion of said contact, whereby the contact is adapted to retain its resiliency due to the lack of heating current in the contact.

12. In a fused cut-out, the combination of a fuse unit comprising an insulating tube having electrical connectors adjacent its opposite ends, and having a tensioned fuse in said tube between said connectors, with a housing member adapted to support said fuse unit, said housing member having a connector carried thereby, and a resilient spring contact carried by said connector, said contact engaging one of the connectors on said fuse unit, and a flexible lead connected to the connector carried by said housing and to the contacting portion of said resilient contact, whereby the major portion of the current is carried by said lead, and the heating of the contact and resultant loss of its resiliency is substantially eliminated.

13. In a fused cut-out, the combination of an insulating housing with a fuse unit, said fuse unit comprising an insulating tube having electrical unit connectors located adjacent its ends, and having a tensioned fuse in said tube connecting said unit connectors, means for securing said fuse unit in said housing, an electrical connector carried by said housing for engaging one of the unit connectors, and a second electrical connector carried by said housing adjacent the other of said unit connectors, a cover movably mounted on said housing and having a bridging contact, said bridging contact engaging the latter of said connectors on said housing and engaging the other of said unit connectors, and means connecting said cover and fuse unit, whereby an opening movement of the cover effects a triple break of the circuit, including all of said connectors and fuse'unit and bridging contacts.

14. In a fused cut-out, the combination of an insulating housing with a fuse unit, said fuse unit comprising an insulating tube having elece trical unit connectors located adjacent its ends, and having a tensioned fuse in said tube cone necting said unit connectors, means for securing said fuse unit in said housing, an electrical connector carried by said housing for engaging one of the unit connectors, and a second electrical connector carried by said housing adjacent the other of said unit connectors, a cover movably mounted on said housing and having a bridging contact, said bridging contact engaging the latter of said connectors on said housing and engaging the other of said unit connectors, and means connecting said cover and fuse unit, whereby an opening movement of the cover effects a triple break of the circuit, including all of said connectors and fuse unit and bridging contacts, said cover being constructed and arranged for pivotal movement on said housing in such manner as to effect a double break of the circuit at said bridging Contact at the upper part of said cut-out first, to avoid the upward travel of an arc from the other break in said circuit.

15. In a fused cut-out, the combination of an insulating housing With a fuse unit comprising an insulating tube, a pair of connectors carried by said tube, and a tensioned fuse in said tube connecting said connectors With connector means carried by the housing for engaging the connectors of said fuse unit, means for pivotally mounting said fuse unit at the upper part of said housing, a cover for said housing, and means for pivotally mounting it on said housing, and latching means operating between said fuse unit and said cover to hold the cover closed when the fuse unit is in its operative position, said latching means automatically becoming disengaged after a predetermined pivotal movement of the fuse unit and cover, by virtue of the location of the points of pivotal support of the fuse unit and the cover.

16. In a housing for fused cut-outs, the com bination of an insulating housing of a frangible nature, said housing being formed with an end wall, a rear wall, and a pair of forwardly projecting side Walls, and having a fuse unit recess therein, With a cover of insulating material, and a pintle for mounting said cover for pivotal movement on the side Walls of said housing, and metal reinforcing means carried by said housing and embracing the rear wall and the side Walls thereof, and extending into engagement with said pintle whereby the breakage of the side Walls adjacent said pintle is substantially eliminated.

17. In a fuse unit for fused cut-outs, the cornbination of an insulating tube with a tubular metallic connector carried by each end of said tube, one of said tube ends being open for passage of a fuse, said fuse unit having its connector adjacent said open end provided with a bore having its axis extending substantially parallel to said insulating tube, a second insulating tube located in said bore, a spring pressed plunger located in said second insulating tube, and a laterally projecting arm carried by said plunger and adapted to serve as a contact for engaging a housing contact.

18. In a fused cut-out, the combination of an insulating housing with a fuse unit comprising an insulating tube,V connectors carried by said tube, and a fuse tensioned in said tube between said connectors, said housing having a recess for said unit, a connector carried by said housing adjacent the upper end of said fuse unit, a cover pivotally mounted on said housing and having a bridging contact for engaging said latter connector and the adjacent connector on said fuse unit, and means for securing the opposite end of said cover to said housing, said bridging contact opening the circuit when the cover is broken.

DAVID C. HUBBARD. 

